1. Hunt Elwood H, Reid Don H, Space David R., Tilton Fred E. Commercial airliner environmental control system—engineering aspects of cabin air quality. Boeing web site, 2007. 〈http://www.boeing.com/commercial/cabinair/ecs.pdf〉.
2. Centre for Applied Microbiology & Research (CAMR). Determination of microbiological efficiency. Report references 443/98, 391/98, 675/00.
3. Health Protection Agency (HPA). An evaluation of filtration against bacterial and viral aerosol challenge. Report no. 76/07.